Anti-inflammatory Diet

What is an anti-inflammatory diet? (And why should I care?)

You’ve probably heard of inflammation. It’s described as a “fire” that’s happening inside your body that can—when it goes on for too long (is chronic) in too big of an area of your body (widespread)—damage your health. Inflammation is involved in several chronic diseases, including diabetes, heart disease, atherosclerosis, and even some neurological issues like depression and Alzheimer’s.

Inflammation can damage normal, healthy tissues and cells. This damage then paves the way for more damage and, eventually, disease.

That’s why we want to reduce chronic, widespread inflammation for better health. A recent study published in the journal Nutrition Reviews looked at several studies to better understand the link between inflammation and what we eat.

How do we measure inflammation?

Inflammation is measured in a similar way to cholesterol: using a blood test. These tests measure levels of inflammatory “biomarkers” in the blood to estimate the levels of inflammation in your entire body.

There are several inflammatory biomarkers that can be measured. This study looked at two that aren’t that commonly used: platelet-activating factor (PAF) and lipoprotein-associated phospholipase A2 (Lp-PLA₂). In this study, researchers looked at the link between diet and how high these two biomarkers for inflammation were.

High levels of PAF are linked with several inflammatory processes. PAF contributes to harmful free-radical oxidation and can trigger the release of other, more well-known inflammatory markers, like IL-6 (interleukin-6), IL-8 (interleukin-8), and TNF-⍺ (tumour-necrosis factor-alpha). According to the study authors, “patients with diabetes, heart failure, acute myocardial infarction, and coronary heart disease have elevated levels of PAF.”

This means that you should aim for low levels of inflammatory PAF in the blood to try to reduce risk of disease.

Lp-PLA₂, on the other hand, has some anti-inflammatory function, however, it’s most often considered to be inflammatory. Like PAF, you want to aim for low levels of Lp-PLA₂ in the blood to try to reduce risk of disease.

Therefore, when it comes to PAF and Lp-PLA₂, you want them to be low as that would indicate lower levels of inflammation in the body, and lower risk of many diseases that are linked with high levels of inflammation.

Yes, what you eat affects your inflammation levels

In this study, the researchers reviewed 16 clinical studies from around the world to figure out what dietary patterns tend to impact levels of PAF and Lp-PLA₂, and they found a trend.

Their research confirmed that certain dietary patterns were associated with lower, while others were associated with higher levels.

Which diets are “anti-inflammatory” (i.e., better for health)?

The “anti-inflammatory” diets linked with lower levels of PAF and Lp-PLA₂ are:

the Mediterranean diet,
vegetarian diet, and
other “heart healthy diets” (like the DASH diet and the “living heart” diet).

The good news is that you can start today! Several of these studies showed that changing your diet can change your levels of inflammation. For example, when healthy people ate a Mediterranean dietary pattern, they had reduced levels of PAF in their blood. And it can even help if you already have a condition linked to high inflammation, like type 2 diabetes. A study of people with diabetes showed that when they started eating a more Mediterranean-style diet, their levels of inflammation dropped even more than those without it.

When it comes to vegetarian diets, we already know that too much red and processed meats contribute to harmful inflammation. Plus, eating more plants and less processed foods has benefits for heart health. The studies reviewed here confirm that people who don’t eat meat tend to have lower levels of inflammatory Lp-PLA₂ than people who do eat meat.

Some studies had participants start eating a “heart healthy” diet. This means that they replaced some of the refined grains with whole grains, and increased the amount of vegetables and legumes that people ate. They found reductions in Lp-PLA₂ levels after 12 weeks. And when the dietary change was accompanied by physical activity, these beneficial changes were seen after just 3 weeks.

You may be wondering which diets are associated with higher levels of inflammation. (And, you probably won’t be surprised.)

The diets linked with higher levels of inflammation were the “western” diets. These are ones that include foods that are more highly processed, like carbonated drinks, fast foods, and salty snacks. Unsurprisingly, the “western” diet is also linked with a higher risk of heart disease.

How can food impact your body’s levels of inflammation?

There are lots of ways that certain foods and diets help to reduce inflammation.

For example, we know that eating more fruits and vegetables reduces some measures of inflammation and is linked with better heart health. Research also shows that some of the bioactive compounds in traditional Mediterranean diet foods naturally inhibit inflammatory PAF by blocking some of the inflammatory processes.

Another way that nutrition can impact your levels of inflammation is related to weight. Losing weight can reduce levels of inflammation, so eating closer to a Mediterranean, vegetarian, or “heart healthy” diet can help to lower weight and inflammation at the same time.

Simple tips to use the power of food to reduce your inflammation

The researchers say, “a range of well-established, healthier dietary patterns may lower inflammation.” These include eating a more Mediterranean, vegetarian, and/or a “heart healthy” diet. What do these diets have in common? Try:

Including more fruits and vegetables into your day, like adding berries to your breakfast, grabbing a banana as a snack, and having a salad with dinner whenever you can
Swapping out refined (“white”) grains for whole grains, like whole wheat, oats, and brown or wild rice
Having nuts, like almonds or walnuts, as snacks
Ditching inflammatory fats like margarine, shortening, and lard, and instead use olive oil
Adding some legumes in your meals, like chickpeas, kidney beans, and lentils

Reference:

English, C. J., Mayr, H. L., Lohning, A. E., & Reidlinger, D. P. (2021). The association between dietary patterns and the novel inflammatory markers platelet-activating factor and lipoprotein-associated phospholipase A2: a systematic review. Nutrition reviews, nuab051. Advance online publication. https://doi.org/10.1093/nutrit/nuab051

https://pubmed.ncbi.nlm.nih.gov/34651191/

https://academic.oup.com/nutritionreviews/advance-article/doi/10.1093/nutrit/nuab051/6397217?log

Backgrounder articles:

About the study:

“To our knowledge, this is the first systematic review to explore the association between dietary patterns, beyond the Mediterranean Diet, and the novel biomarkers PAF and Lp-PLA2.”
Note that systematic reviews are very strong studies because of the high standards for searching for, including, and analyzing studies that are included.
Most studies of inflammation and nutrition have looked at the immediate impact (e.g., blood levels of inflammatory markers) of individual foods. This one looked at studies done on inflammation and dietary patterns, not individual foods.
“This review was comprehensive and systematic; however, the analysis is limited by the small number of studies adhering to the inclusion criteria assessing dietary patterns and these novel biomarkers.” Basically, because of their strong criteria to select studies, and how novel these biomarkers are, there weren’t too many studies available to include, so more research is needed in this area.
Some nerdy insight into Lp-PLA₂: This biomarker is an enzyme that can break down inflammatory PAF and seems to be protective when bound to the “good” cholesterol HDL. But, despite these anti-inflammatory roles, Lp-PLA₂ seems to also promote harmful inflammation and oxidation and is considered to be a risk factor for atherosclerosis, heart disease, and stroke. Unfortunately, Lp-PLA₂ tips more toward inflammation than anti-inflammation, so overall, it is considered to be a biomarker of inflammation.
Conclusion: “There is limited evidence and considerable diversity in existing studies investigating dietary patterns and the novel inflammatory markers PAF and Lp-PLA2. A range of well-established dietary patterns has potential to improve these novel markers, including Mediterranean, vegetarian, and other heart-healthy dietary patterns. Conversely, Western dietary patterns are associated with higher levels of inflammation, as measured by these markers. More, well-designed studies are needed to confirm these findings and identify other dietary patterns that could positively affect inflammation.”
Note that all studies have limitations. In this study, because they are looking at novel/new/uncommon biomarkers (PAF and Lp-PLA₂), they only found 16 studies to consider. The researchers recommend that more studies are done looking at these two biomarkers, and also that new studies be larger than the ones they’ve found.
Also, because PAF and Lp-PLA₂ are novel biomarkers, there isn’t too much known about the “normal” concentrations of them in healthy people. This makes it hard to determine which levels are considered to be “high” or “low” so these can be effectively used. More research is needed on the normal levels and functions of PAF and Lp-PLA₂.
Overall, we can’t say that the Mediterranean/vegetarian/heart healthy diet prevents/treats inflammation-based diseases, we can say that Mediterranean/vegetarian/heart healthy diets appear to reduce biomarkers of inflammation which may lower the risk for many chronic diseases or that Mediterranean/vegetarian/heart healthy diets are linked with lower levels of inflammation (correlation does not equal causation). Here’s a blog post I wrote on this concept: https://leesaklich.com/health-research/correlation-does-not-equal-causation/
Study strength is rated a 7/7 according to this chart (systematic review study), but it’s only based on 16 studies and more research is needed: https://www.compoundchem.com/2015/04/09/scientific-evidence/